25 lines
963 B
Markdown
25 lines
963 B
Markdown
# dnsmasq: busy loop in proxy DHCP with a tagged range
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Found 2026-10-29 while testing Rollcall's proxy DHCP mode (gdb on a stuck lab
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rack controller). Affects dnsmasq 2.91 (Debian 13) and 2.93 (latest release).
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Rollcall works around it by leaving the tag off proxy ranges
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(`cmd/rollcall/network.go`, `dnsmasqConfig`).
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| File | |
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| `report.txt` | the report to send upstream (plain text, patch inline) |
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| `repro.sh` | reproducer: `sudo ./repro.sh /path/to/dnsmasq` (two netns + veth, two PXE DISCOVERs) |
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| `0001-proxy-dhcp-reset-context-tags.patch` | one-line fix against 2.93, applies with `patch -p1` or `git apply` |
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Results on a Debian 13 VM:
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| dnsmasq | Configuration | CPU after two PXE requests |
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| 2.91 (Debian) | tagged proxy range, `log-dhcp` | 100% |
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| 2.93 | same | 100% |
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| 2.93 + patch | same | 0% |
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| 2.93 | no `log-dhcp`, `dhcp-option` for an absent tag | 69% |
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| 2.93 + patch | same | 0% |
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Status: not reported yet.
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